• Support PF! Buy your school textbooks, materials and every day products Here!

Friction/acceleration of cylinder

  • Thread starter fw029
  • Start date
  • #1
1
0

Homework Statement


given a situation (http://teachingphysics.files.wordpress.com/2009/03/spool-21.png" [Broken]) where a string with tension is pulling a spool of mass m from the bottom, what would be the directions of acceleration and friction? note: there's no slip at all.

given: tension equals weight (mg). the spool has rotational inertia I=(1/2)mr^2


Homework Equations


(not trying to calculate anything)


The Attempt at a Solution


the spool would wind up, so velocity would be to the right I think. if you make the axis at where it touches the ground, tension is the only force providing torque...so I think angular acceleration would be clockwise, and so linear acceleration would be pointing right, and friction would be towards the left?

I'm not really sure, so any help would be appreciated.
 
Last edited by a moderator:

Answers and Replies

  • #2
Delphi51
Homework Helper
3,407
10
Welcome to PF.
It sure looks to me like pulling the string will try to unwind the spool and make it turn counterclockwise so it will try to go left. Friction will give it a grip on the table. You'll have a left force AND a right force which will have to be calculated to see which way it goes. It may well go right and wind the string if the friction is sufficiently strong.
 
  • #3
hint: since there is no slip acceleration at point of contact is zero
 

Related Threads on Friction/acceleration of cylinder

Replies
2
Views
6K
  • Last Post
2
Replies
34
Views
2K
  • Last Post
Replies
10
Views
4K
Replies
13
Views
2K
  • Last Post
Replies
18
Views
4K
Replies
1
Views
352
Replies
2
Views
4K
Replies
1
Views
1K
Replies
1
Views
680
Replies
1
Views
4K
Top